Why use monolithic microwave integrated circuits (MMICs) in aerospace applications

Why use monolithic microwave integrated circuits (MMICs) in aerospace applications

Optimizing electronics, PCBAs and assemblies for size, weight and power or SWaP is a major direction in aerospace system development. The pursuit of this goal has led to a growing preference and use of optoelectronics as opposed to discrete circuits as monolithic microwave integrated circuits (MMICs). Let's take a deeper look at these devices. Especially when and why they are used on ships.

What is a Monolithic Microwave Integrated Circuit (MMIC)?

As with many advances in electronics, the military and government were catalysts for early research into the process of building ICs that operate in the microwave frequency range (300MHz to 300GHz). At the time, in the mid-1970s, discrete components were mostly placed manually. The propensity for human error and the lack of precision of the technique are the main factors that have piqued the interest of MMIC.

MMICs are highly dense component packages that utilize and process microwave signals internally. Typical materials used to construct these components (done by machine rather than by hand) are GaAs, InP, GaN and SiGe. The many advantages of these components (listed below) explain why they are preferred by many for avionics roles.

Advantages of MMICs

l High component density

l Small packaging

l Highly accurate internal component placement

l Fast signal propagation

l Low overall cost for large quantities

lHigh reliability wire bonding

The list above clearly shows how the use of MMICs can help drive SWaP optimization for aerospace system development. Now, the disadvantages of using MMICs must also be considered. These are listed below.

Disadvantages of MMICs

l Low power capability

l Can be expensive to manufacture in small quantities

l No design changes can be made during manufacturing

l Custom PCB dimensions are often required, which makes assembly more challenging.

lCannot be reworked.

Trimming is used to compensate for manufacturer-affecting component parameter variations, which can be a problem for MMICs. difficult or impossible to achieve.

As this list shows, choosing to use an MMIC does come with some burdens, a large part of which will affect the contract manufacturer (CM) building your board. Armed with the key advantages and disadvantages of MMICs, we can determine when and why we should deploy them in our aerospace application development.

Using MMICs for Aerospace Applications

When developing PCBAs or electronics for aerospace entities, the use of optical and microwave components may be required or preferred. In other cases, design guidelines may not extend to components or packages, and it is up to you to use MMICs. Before choosing to do so, you should know whether this is the best option.